I've been towing a 2013 Kia Soul+ 6-speed manual for several years without any problems. Several weeks ago I took my Soul to the Kia dealer for some expensive warranty work (a/c compressor). Absolutely no problem with the warranty. Kia covered 100% of the work. The Service Manager knew it was a towed as he commented on the good job the RV dealer did on the Kia. So at least in my instance, towing a Soul did not invalidate it's warranty.